One embodiment of the present invention provides a system that estimates a power utilization of a computer system. During operation, a set of performance parameters of the computer system is monitored, wherein the computer system includes a processor. Then the power utilization of the computer system is estimated based on the set of performance parameters and a power-utilization model, wherein the power-utilization model was trained by measuring a power utilization of the computer system while the processor is operating at a first frequency and measuring a power utilization of the computer system while the processor is operating at a second frequency.